[blue00gt]

Actually, in 1st and 2nd gear is where you gain most of the time in the 1/4 mile by changing gears. It's all about getting the motor in the powerband faster.
As for the example that was posted, if you top out at 35mph in 1st with stock 3.27 gears, you would top out at 28mph with 4.10s (just divide 3.27 by 4.10 and multiply by the speed).
Gears don't change the powerband of the motor, they are just torque multiplication. If you want it to pull more in the lower revs you need to change parts on the engine. Even with steeper gears if you are lugging it at low rpms it's still going to feel slow. The point of the gears is to get your rpms up.
If you want your car to pull more at low rpms you should give up and put a stock 5.0 in it. Mod motors don't really start to pull until near 4k. If you re-cammed your motor to make more power down low you'll just lose top end and end up with a slower car. Sounds like you want a truck or luxury car type motor.